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Wang T, Zhang F, Yang L, Fang XW, Zhou SH, Kramer MJ, Wang CZ, Ho KM, Napolitano RE. A computational study of diffusion in a glass-forming metallic liquid. Sci Rep 2015; 5:10956. [PMID: 26055394 PMCID: PMC4460728 DOI: 10.1038/srep10956] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 05/01/2015] [Indexed: 11/24/2022] Open
Abstract
Liquid phase diffusion plays a critical role in phase transformations (e.g. glass transformation and devitrification) observed in marginal glass forming systems such as Al-Sm. Controlling transformation pathways in such cases requires a comprehensive description of diffusivity, including the associated composition and temperature dependencies. In the computational study reported here, we examine atomic diffusion in Al-Sm liquids using ab initio molecular dynamics (AIMD) and determine the diffusivities of Al and Sm for selected alloy compositions. Non-Arrhenius diffusion behavior is observed in the undercooled liquids with an enhanced local structural ordering. Through assessment of our AIMD result, we construct a general formulation for Al-Sm liquid, involving a diffusion mobility database that includes composition and temperature dependence. A Volmer-Fulcher-Tammann (VFT) equation is adopted for describing the non-Arrhenius behavior observed in the undercooled liquid. The composition dependence of diffusivity is found quite strong, even for the Al-rich region contrary to the sole previous report on this binary system. The model is used in combination with the available thermodynamic database to predict specific diffusivities and compares well with reported experimental data for 0.6 at.% and 5.6 at.% Sm in Al-Sm alloys.
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Affiliation(s)
- T. Wang
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
| | - F. Zhang
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
| | - L. Yang
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
| | - X. W. Fang
- Kuang-Chi Institute of Advanced Technology, Shenzhen, Guangdong 518000, China
| | - S. H. Zhou
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
| | - M. J. Kramer
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
- Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA
| | - C. Z. Wang
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
| | - K. M. Ho
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
| | - R. E. Napolitano
- Division of Materials Sciences and Engineering, Ames Laboratory, US DOE, Ames, IA 50011, USA
- Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA
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